Silicon metal (Si) reacts with nitrogen gas (N2) to give silicon nitride (Si3N4) based on the following balanced reaction: 3 Si + 2 N2 -->?

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2017-11-22 12:15 am

Silicon metal (Si) reacts with nitrogen gas (N2) to give silicon nitride (Si3N4) based on the following balanced reaction:

3 Si + 2 N2 --> Si3N4

Determine the following if 5.00 grams of silicon metal reacts with 4.00 grams of nitrogen gas. Give three significant figures for your answers.

Moles of Si reactant:_____

Moles of N2 reactant:_____

更新1:

Which reagent is the limiting reagent of this reaction? Enter '1' for Si or '2' for N2 ____

回答 (1)

戇戇居士

2017-11-22 12:32 am

Molar mass of Si = 28.09 g/mol
Molar mass of N₂ = 14.01 × 2 = 28.02 g/mol

Initial number of moles of Si = (5.00 g) / (28.09 g/mol) = 0.178 mol
Initial number of moles of N₂ = (4.00 g) / (28.02 g/mol) = 0.143 mol

3 Si + 2 N₂ → Si₃N₄
Mole ratio Si : N₂ = 3 : 2

When 0.178 mol Si completely reacts, N₂ needed = (0.178 mol) × (2/3) = 0.119 mol < 0.143 mol
Hence, N₂ is in excess, and thus Si is the limiting reactant (limiting reagent).

Moles of Si reactant (completely reacted) = 0.178 mol
Moles of N₂ reactant = (0.178 mol) × (2/3) = 0.119 mol

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